A typical carton-liner assembly includes a carton in the form a six-sided parallelopiped enclosure having opposing top and bottom walls, front and back balls, and side walls formed from corresponding panels and flaps defined on a unitary paperboard blank. The assembly further includes a liner constructed and arranged to fit within the carton. The liner has a front panel, opposing side panels, and, if desired, a partial or full back panel opposing the front panel. Furthermore, the liner may be either a full-height liner extending from the top wall to the bottom wall of the carton or a partial-height liner extending from the top wall of the carton to a location spaced away from the bottom wall of the carton. The assembly may be provided with a reclosure feature of the type described in U.S. Pat. Nos. 5,154,343, 5,265,799, and 5,314,114 to Stone. This reclosure feature employs an overhanging liner flap creating two layers of paperboard along the upper portion of the liner front panel. Moreover, the assembly may be provided with a handle extending along an upper portion of the front and side panels of the carton blank. The ends of the handle are attached to or protrude through the side panels of the carton blank.
The carton-liner assembly is manufactured using high speed packaging equipment. In particular, the carton and liner are formed from respective die-cut unitary blanks provided with working scores. A working score is defined herein as a score which permits the associated blank to be easily folded 180 degrees about the score during production of the assembly. After die-cutting the blanks, the liner blank is positioned over and adhered to the inner surface of the carton blank with the working scores of the liner blank approximately aligned with the working scores of the carton blank. Next, the liner and carton blanks are folded 180 degrees about the aligned working scores to create a finished, glued flat assembly in flattened tubular form.
With the carton-liner assembly in flattened tubular form, the assembly is stacked in a case along with other identical assemblies by hand or by using high-speed case packing equipment. After the case is shipped to a customer for form-fill-seal operations, the assembly is stacked once again with other such assemblies in the hopper of the form-fill-seal equipment. A drawback of the carton-liner assembly is that a plurality of the flattened tubular assemblies do not stack evenly if a partial-height liner, a reclosure feature, or a handle is employed on the carton-liner assembly. Each of the foregoing features increases the thickness of a flattened tubular assembly at the upper portion thereof, but not at the lower portion thereof. As a result, one portion of a stack of such carton-liner assemblies will be higher (vertical stack) or wider (horizontal stack) than another portion of the stack. This, in turn, may generate an imbricate (shingle) structure, cause a portion of the stack to sag, or cause some assemblies in the stack to separate themselves from the remainder of the stack. The stacking problems hinder case packing and form-fill-seal operations, thereby reducing manufacturing efficiency.
A need therefore exists for a carton-liner assembly which overcomes the aforementioned shortcomings associated with existing carton-liner assemblies.